1. Technical Field of the Invention
The present invention relates to a battery pack and battery pack separator used in applications such as a car power source apparatus.
2. Description of the Related Art
In a car power source apparatus, many individual batteries (battery cells) are connected in series to increase output voltage and output power. Since this power source apparatus is charged and discharged with high currents, battery temperatures rise. Further, because the power source apparatus must be usable even in extreme high temperature environments, forced cooling of the batteries is essential. Power source apparatus on-board present day hybrid cars are cooled by forced ventilation of the batteries with cooling air delivered by fan.
Since batteries in these power source apparatus are cooled by air, rapid cooling is difficult when abnormal battery temperature rise occurs. Further, because ventilation and cooling is via air, which has low heat capacity, it is difficult to cool many batteries to a uniform temperature.
As a battery pack to correct these drawbacks, Japanese Patent Application Disclosure 2004-362879 describes a cooling configuration as shown in FIG. 1. Here, cooling air channels 72 are established by separators 70 disposed between adjacent battery cells 71, and cooling air is delivered through those cooling air channels 72. A battery pack having this type of structure is shown in the plan view of FIG. 2. Here, cooling air is delivered into an air duct 74 provided along the battery cell 71 stacking direction of one side (bottom side in FIG. 2) of the battery pack. This cooling air is divided, passed through the cooling air channels 72 formed between adjacent battery cells 71, collected at the opposite side (top side in FIG. 2) of the battery pack, and discharged to the outside.